Guess I must be on a different train than you guys...
I gave up on the shuttle flights between BOS-LGA a few weeks before 9/11, and I haven't gone back. My first class Acela seat is still less money than a shuttle ticket, and that's before I factor in parking at Logan and a car service both ways in NY. In first on Acela Express you get a meal (breakfast tends to be better than dinner, but it is a hot meal)(no poor excuse for a bagel snack here ala Shuttle); I can actually use my cell phone for the bulk of the trip; there are outlets to plug in my laptop, cellphone, etc; there is a clean, large bathroom; and contrary to the ads - the train is faster than flying in rush hour. In fact, my associate insisted on flying recently - going to NY I left 10 minutes earlier, and we literally walked into the building in midtown at the same time; on the return we left at the same time, he got caught in traffic on the way to LGA, and I beat him home by over 1.5 hours. But the big thing is there are no hassles - I park near the platform at the 128 Station and take a few steps to board. In NY I can generally get to my appointments on the subway, and most of the time never have to go outside, so the weather is not an issue. I wish the train was faster - it could be if they were able to clean up the tracks in NY/CT - but it is still a relaxing trip and more often than not faster overall the flying.